Caltech News tagged with "HIV"http://www.caltech.edu/news/tag_ids/30/rss.xml
enA Molecular Arms Race: The Immune System Versus HIVhttp://www.caltech.edu/news/molecular-arms-race-immune-system-versus-hiv-46076
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Watson Lecture Preview</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Douglas Smith</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Watson-Lecture-Bjorkman-02-NEWS-WEB.jpeg?itok=rYmqEfW6" alt="" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Yunji Wu/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p><em>It is now more than 30 years after the first AIDS epidemic, and an effective vaccine against HIV does not yet exist—partly because the virus quickly mutates to evade the vaccine's antibodies. </em><em>On Wednesday, April 1, at 8 p.m. in Caltech's Beckman Auditorium, </em><em>Pamela J. Bjorkman, Caltech's </em><em>Max Delbrück Professor of Biology and an investigator with the Howard Hughes Medical Institute, will describe ways to neutralize </em><em>that mutational advantage. </em><em>Admission is free.</em></p><p> </p><p><strong>What do you do?</strong></p><p>We are structural biologists who use various imaging techniques to look at biological macromolecules and assemblies, sometimes in purified forms and sometimes in tissues. For example, we study HIV proteins alone, on viruses, and on viruses in tissues during an infection. Utilizing high-resolution structures of individual proteins, we are trying to apply our knowledge of the chemistry of protein-protein interactions to understanding what makes some antibodies produced by HIV-infected people good at neutralizing viruses and other antibodies less effective. We then try to reengineer good antibodies to make them even better in hopes that they could be used therapeutically to prevent or treat HIV infection.</p><p> </p><p><strong>What's the neatest thing about what you do?</strong></p><p>Using imaging techniques such as X-ray crystallography and electron microscopy, we can visualize structures in three dimensions, sometimes even localizing all of the atoms in a protein structure. This feels a bit like spying on nature—forcing her to reveal secrets that we can hopefully use to combat HIV/AIDS.</p><p> </p><p><strong>How did you get into this line of work?</strong></p><p>I was hooked after taking chemistry in high school. I knew then that I wanted to use chemistry to understand biology. I became interested in HIV about 10 years ago when I started teaching the Caltech freshman biology class and used HIV as a model system to understand basic principles of biology, especially evolution. HIV is an amazing example of successful evolution against which the human immune system loses, but I hope that we can win the war against HIV through a fundamental understanding of how it works.</p><p> </p><p><strong><em>Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at </em></strong><a href="http://itunes.apple.com/us/itunes-u/watson-lectures-sd/id422627541"><strong><em>Caltech's iTunes U site</em></strong></a><strong><em>.</em></strong></p></div></div></div>Thu, 26 Mar 2015 00:50:38 +0000dsmith46076 at http://www.caltech.eduGenetically Engineered Antibodies Show Enhanced HIV-Fighting Abilitieshttp://www.caltech.edu/news/genetically-engineered-antibodies-show-enhanced-hiv-fighting-abilities-45491
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kimm Fesenmaier</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Bjorkman-HIV-Illustration-ARTICLE-NEWS-WEB.jpg?itok=5srV_bYO" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Antibodies generally attack a virus by binding with both of their "arms" to two of the spikes sticking up from the surface of the virus. Caltech researchers propose that HIV&#039;s low spike density makes it hard for antibodies to do this. The biologists engineered antibody-based molecules that can bind to a single HIV spike with both arms and showed that the new molecules are more than 100 times better than naturally occurring antibodies at binding to and neutralizing HIV.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Lance Hayashida/Caltech Office of Strategic Communications and the Bjorkman Laboratory/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Capitalizing on a new insight into HIV's strategy for evading antibodies—proteins produced by the immune system to identify and wipe out invading objects such as viruses—Caltech researchers have developed antibody-based molecules that are more than 100 times better than our bodies' own defenses at binding to and neutralizing HIV, when tested in vitro. The work suggests a novel approach that could be used to engineer more effective HIV-fighting drugs.</p><p>"Based on the work that we have done, we now think we know how to make a really potent therapeutic that would not only work at relatively low concentrations but would also force the virus to mutate along pathways that would make it less fit and therefore more susceptible to elimination," says <a href="http://www.its.caltech.edu/~bjorker/">Pamela Bjorkman</a>, the Max Delbrück Professor of Biology and an investigator with the Howard Hughes Medical Institute. "If you were able to give this to someone who already had HIV, you might even be able to clear the infection."</p><p>The researchers describe the work in the January 29 issue of <em>Cell</em>. Rachel Galimidi, a graduate student in Bjorkman's lab at Caltech, is lead author on the paper.</p><p>The researchers hypothesized that one of the reasons the immune system is less effective against HIV than other viruses involves the small number and low density of spikes on HIV's surface. These spikes, each one a cluster of three protein subunits, stick up from the surface of the virus and are the targets of antibodies that neutralize HIV. While most viruses are covered with hundreds of these spikes, HIV has only 10 to 20, making the average distance between the spikes quite long.</p><p>That distance is important with respect to the mechanism that naturally occurring antibodies use to capture their viral targets. Antibodies are Y-shaped proteins that evolved to grab onto their targets with both "arms." However, if the spikes are few and far between—as is the case with HIV—it is likely that an antibody will bind with only one arm, making its connection to the virus weaker (and easier for a mutation of the spike to render the antibody ineffective).</p><p>To test their hypothesis, Bjorkman's group genetically engineered antibody-based molecules that can bind with both arms to a <em>single</em> spike. They started with the virus-binding parts, or Fabs, of broadly neutralizing antibodies—proteins produced naturally by a small percentage of HIV-positive individuals that are able to fight multiple strains of HIV until the virus mutates. When given in combination, these antibodies are quite effective. Rather than making Y-shaped antibodies, the Caltech group simply connected two Fabs—often from different antibodies, to mimic combination therapies—with different lengths of spacers composed of DNA.</p><p>Why DNA? In order to engineer antibodies that could latch onto a spike twice, they needed to know which Fabs to use and how long to make the connection between them so that both could readily bind to a single spike. Previously, various members of Bjorkman's group had tried to make educated guesses based on what is known of the viral spike structure, but the large number of possible variations in terms of which Fabs to use and how far apart they should be, made the problem intractable.</p><p>In the new work, Bjorkman and Galimidi struck upon the idea of using DNA as a "molecular ruler." It is well known that each base pair in double-stranded DNA is separated by 3.4 angstroms. Therefore, by incorporating varying lengths of DNA between two Fabs, they could systematically test for the best neutralizer and then derive the distance between the Fabs from the length of the DNA. They also tested different combinations of Fabs from various antibodies—sometimes incorporating two different Fabs, sometimes using two of the same.</p><p>"Most of these didn't work at all," says Bjorkman, which was reassuring because it suggested that any improvements the researchers saw were not just created by an artifact, such as the addition of DNA.</p><p>But some of the fabricated molecules worked very well. The researchers found that the molecules that combined Fabs from two different antibodies performed the best, showing an improvement of 10 to 1,000 times in their ability to neutralize HIV, as compared to naturally occurring antibodies. Depending on the Fabs used, the optimal length for the DNA linker was between 40 and 62 base pairs (corresponding to 13 and 21 nanometers, respectively).</p><p>Taking this finding to the next level in the most successful of these new molecules, the researchers replaced the piece of DNA with a protein linker of roughly the same length composed of 12 copies of a protein called tetratricopeptide repeat. The end product was an all-protein antibody-based reagent designed to bind with both Fabs to a single HIV spike.</p><p>"That one also worked, showing more than 30-fold average increased potency compared with the parental antibodies," says Bjorkman. "That is proof of principle that this can be done using protein-based reagents."</p><p>The greater potency suggests that a reagent made of these antibody-based molecules could work at lower concentrations, making a potential therapeutic less expensive and decreasing the risk of adverse reactions in patients.</p><p>"I think that our work sheds light on the potential therapeutic strategies that biotech companies should be using—and that we <em>will</em> be using—in order to make a better antibody reagent to combat HIV," says Galimidi. "A lot of companies discount antibody reagents because of the virus's ability to evade antibody pressure, focusing instead on small molecules as drug therapies. Our new reagents illustrate a way to get around that."</p><p>The Caltech team is currently working to produce larger quantities of the new reagents so that they can test them in humanized mice—specialized mice carrying human immune cells that, unlike most mice, are sensitive to HIV.</p><p>Along with Galimidi and Bjorkman, additional Caltech authors on the paper, <a href="http://resolver.caltech.edu/CaltechAUTHORS:20150121-095951269">"Intra-Spike Crosslinking Overcomes Antibody Evasion by HIV-1,"</a> include Maria Politzer, a lab assistant; and Anthony West, a senior research specialist. Joshua Klein, a former Caltech graduate student (PhD '09), and Shiyu Bai, a former technician in the Bjorkman lab, also contributed to the work; they are currently at Google and Case Western Reserve University School of Medicine, respectively. Michael Seaman of Beth Israel Deaconess Medical Center and Michel Nussenzweig of the Rockefeller University in New York are also coauthors. The work was supported by the National Institutes of Health through a Director's Pioneer Award and a grant from the HIV Vaccine Research and Design Program, as well as grants from the Collaboration for AIDS Vaccine Discovery and the Bill and Melinda Gates Foundation. Nussenzweig is also an investigator with the Howard Hughes Medical Institute.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.caltech.edu/news/detailed-look-hiv-action-41908" class="pr-link">A Detailed Look at HIV in Action</a></div></div></div>Tue, 27 Jan 2015 21:23:18 +0000kfesenma45491 at http://www.caltech.eduA New Way to Prevent the Spread of Devastating Diseaseshttp://www.caltech.edu/news/new-way-prevent-spread-devastating-diseases-43753
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kimm Fesenmaier</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-gif view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/Baltimore-VIP-NEWS-WEB.gif?itok=hQLV5JdI" alt="" /></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>For decades, researchers have tried to develop broadly effective vaccines to prevent the spread of illnesses such as HIV, malaria, and tuberculosis. While limited progress has been made along these lines, there are still no licensed vaccinations available that can protect most people from these devastating diseases.</p><p>So what are immunologists to do when vaccines just aren't working?</p><p>At Caltech, Nobel Laureate <a href="http://www.bbe.caltech.edu/content/david-baltimore">David Baltimore</a> and his colleagues have approached the problem in a different way. Whereas vaccines introduce substances such as antigens into the body hoping to illicit an appropriate immune response—the generation of either antibodies that might block an infection or T cells capable of attacking infected cells—the Caltech team thought: Why not provide the body with step-by-step instructions for producing specific antibodies that have been shown to neutralize a particular disease?</p><p>The method they developed—originally to trigger an immune response to HIV—is called vectored immunoprophylaxis, or VIP. The technique was so successful that it has since been applied to a number of other infectious diseases, including influenza, malaria, and hepatitis C.</p><p>"It is enormously gratifying to us that this technique can have potentially widespread use for the most difficult diseases that are faced particularly by the less developed world," says Baltimore, president emeritus and the Robert Andrews Millikan Professor of Biology at Caltech.</p><p><span style="line-height: 1.538em;">VIP relies on the prior identification of one or more antibodies that are able to prevent infection in laboratory tests by a wide range of isolated samples of a particular pathogen. Once that has been done, researchers can incorporate the genes that encode those antibodies into an adeno-associated virus (AAV), a small, harmless virus that has been useful in gene-therapy trials. When the AAV is injected into muscle tissue, the genes instruct the muscle tissue to generate the specified antibodies, which can then enter the circulation and protect against infection.</span></p><p>In 2011, the Baltimore group reported in <em>Nature</em> that they had used the technique to deliver antibodies that effectively <a href="http://www.caltech.edu/content/biologists-deliver-neutralizing-antibodies-protect-against-hiv-infection-mice">protected mice from HIV infection</a>. Alejandro Balazs was lead author on <a href="http://resolver.caltech.edu/CaltechAUTHORS:20110922-140553274">that paper</a> and was a postdoctoral scholar in the Baltimore lab at the time.</p><p>"We expected that at some dose, the antibodies would fail to protect the mice, but it never did—even when we gave mice 100 times more HIV than would be needed to infect seven out of eight mice," said Balazs, now at the Ragon Institute of MGH, MIT and Harvard. "All of the exposures in this work were significantly larger than a human being would be likely to encounter."</p><p>At the time, the researchers noted that the leap from mice to humans is large but said they were encouraged by the high levels of antibodies the mice were able to produce after a single injection and how effectively the mice were protected from HIV infection for months on end. Baltimore's team is now working with a manufacturer to produce the materials needed for human clinical trials that will be conducted by the Vaccine Research Center at the National Institutes of Health.</p><p><span style="line-height: 1.538em;">Moving on from HIV, the Baltimore lab's next goal was protection against influenza A. Although reasonably effective influenza vaccines exist, each year more than 20,000 deaths, on average, are the result of seasonal flu epidemics in the United States. We are encouraged to get flu shots every fall because the influenza virus is something of a moving target—it evolves to avoid resistance. There are also many different strains of influenza A (e.g. H1N1 and H3N2), each incorporating a different combination of the various forms of the proteins hemagglutinin (H) and neuraminidase (N). To chase this target, the vaccine is reformulated each year, but sometimes it fails to prevent the spread of the strains that are prevalent that year.</span></p><p><span style="line-height: 1.538em;">But about five years ago, researchers began identifying a new class of anti-influenza antibodies that are able to prevent infection by many, many strains of the virus. Instead of binding to the head of the influenza virus, as most flu-fighting antibodies do, these new antibodies target the stalk that holds up the head. And while the head is highly adaptable—meaning that even when mutations occur there, the virus can often remain functional—the stalk must basically remain the same in order for the virus to survive. So these stalk antibodies are very hard for the virus to mutate against.</span></p><p>In 2013, the Baltimore group stitched the genes for two of these new antibodies into an AAV and showed that mice injected with the vector were protected against multiple flu strains, including all H1, H2, and H5 influenza strains tested. This was even true of older mice and those without a properly functioning immune system—a particularly important finding considering that most deaths from the flu occur in the elderly and immunocompromised populations. The group reported <a href="http://resolver.caltech.edu/CaltechAUTHORS:20130812-135356477">its results</a> in the journal <em>Nature Biotechnology</em>.</p><p>"We have shown that we can protect mice completely against flu using a kind of antibody that doesn't need to be changed every year," says Baltimore. "It is important to note that this has not been tested in humans, so we do not yet know what concentration of antibody can be produced by VIP in humans. However, if it works as well as it does in mice, VIP may provide a plausible approach to protect even the most vulnerable patients against epidemic and pandemic influenza."</p><p>Now that the Baltimore lab has shown VIP to be so effective, other groups from around the country have adopted the Caltech-developed technique to try to ward off malaria, hepatitis C, and tuberculosis.</p><p>In August, a team led by Johns Hopkins Bloomberg School of Public Health reported in the <em>Proceedings of the National Academy of Sciences </em>(<em>PNAS</em>) that as many as 70 percent of mice that they had injected by the VIP procedure were protected from infection with malaria by <em>Plasmodium falciparum</em>, the parasite that carries the most lethal of the four types of the disease. A subset of mice in the study produced particularly high levels of the disease-fighting antibodies. In those mice, the immunization was 100 percent effective.</p><p>"This is also just a first-generation antibody," says Baltimore, who was a coauthor on the <a href="http://resolver.caltech.edu/CaltechAUTHORS:20140820-085536231"><em>PNAS</em> study</a>. "Knowing now that you can get this kind of protection, it's worth trying to get much better antibodies, and I trust that people in the malaria field will do that."</p><p>Most recently, a group led by researchers from The Rockefeller University showed that three hepatitis-C-fighting antibodies delivered using VIP were able to protect mice efficiently from the virus. The results were published in the September 17 issue of the journal <em>Science Translational Medicine. </em>The researchers also found that the treatment was able to temporarily clear the virus from mice that had already been infected. Additional work is needed to determine how to prevent the disease from relapsing. Interestingly, though, the work suggests that the antibodies that are effective against hepatitis C, once it has taken root in the liver, may work by protecting uninfected liver cells from infection while allowing already infected cells to be cleared from the body. </p><p>An additional project is currently evaluating the use of VIP for the prevention of tuberculosis—a particular challenge given the lack of proven tuberculosis-neutralizing antibodies.</p><p>"When we started this work, we imagined that it might be possible to use VIP to fight other diseases, so it has been very exciting to see other groups adopting the technique for that purpose," Baltimore says. "If we can get positive clinical results in humans with HIV, we think that would really encourage people to think about using VIP for these other diseases."</p><p>Baltimore's work is supported by funding from the National Institute of Allergy and Infectious Disease, the Bill and Melinda Gates Foundation, the Caltech-UCLA Joint Center for Translational Medicine, and a Caltech Translational Innovation Partnership Award.</p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://images.caltech.edu/news_releases/2011_11_30_baltimore/" class="pr-link">Video</a></div><div class="field-item odd"><a href="http://www.caltech.edu/content/biologists-deliver-neutralizing-antibodies-protect-against-hiv-infection-mice" class="pr-link">Biologists Deliver Neutralizing Antibodies that Protect Against HIV Infection in Mice</a></div><div class="field-item even"><a href="http://www.bbe.caltech.edu/content/caltech-developed-method-delivering-hiv-fighting-antibodies-proven-even-more-promising" class="pr-link">Caltech-Developed Method for Delivering HIV-Fighting Antibodies Proven Even More Promising</a></div></div></div>Thu, 18 Sep 2014 16:07:11 +0000kfesenma43753 at http://www.caltech.eduCaltech-Developed Method for Delivering HIV-Fighting Antibodies Proven Even More Promisinghttp://www.caltech.edu/news/caltech-developed-method-delivering-hiv-fighting-antibodies-proven-even-more-promising-41989
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kimm Fesenmaier</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-video file-video-youtube view-mode-full_grid_9 clearfix ">
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<h2 class="element-invisible">Caltech Biologists Deliver Neutralizing Antibodies that Protect Against HIV in Mice</h2>
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<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/grid_9/s3/media-youtube/c4FzBC8pqDc.jpg?itok=xehzNqJu" width="450" height="300" alt="Caltech Biologists Deliver Neutralizing Antibodies that Protect Against HIV in Mice" /> </div>
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</a><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Caltech biologists David Baltimore and Alejandro Balazs discuss their novel approach to HIV prevention: a delivery method for neutralizing antibodies, which protect against HIV infection in mice.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>In 2011, biologists at the California Institute of Technology (Caltech) demonstrated <a href="http://www.caltech.edu/content/biologists-deliver-neutralizing-antibodies-protect-against-hiv-infection-mice">a highly effective method for delivering HIV-fighting antibodies</a> to mice—a treatment that protected the mice from infection by a laboratory strain of HIV delivered intravenously. Now the researchers, led by Nobel Laureate David Baltimore, have shown that the same <a href="http://images.caltech.edu/news_releases/2011_11_30_baltimore/">procedure</a> is just as effective against a strain of HIV found in the real world, even when transmitted across mucosal surfaces.</p><p>The findings, which appear in the February 9 advance online publication of the journal <em>Nature Medicine</em>, suggest that the delivery method might be effective in preventing vaginal transmission of HIV between humans.</p><p>"The method that we developed has now been validated in the most natural possible setting in a mouse," says Baltimore, president emeritus and the Robert Andrews Millikan Professor of Biology at Caltech. "This procedure is extremely effective against a naturally transmitted strain and by an intravaginal infection route, which is a model of how HIV is transmitted in most of the infections that occur in the world."</p><p>The new delivery method—called Vectored ImmunoProphylaxis, or VIP for short—is not exactly a vaccine. Vaccines introduce substances such as antigens into the body to try to get the immune system to mount an appropriate attack—to generate antibodies that can block an infection or T cells that can attack infected cells. In the case of VIP, a small, harmless virus is injected and delivers genes to the muscle tissue, instructing it to generate specific antibodies. </p><p>The researchers emphasize that the work was done in mice and that the leap from mice to humans is large. The team is now working with the Vaccine Research Center at the National Institutes of Health to begin clinical evaluation.</p><p>The study, <a href="http://resolver.caltech.edu/CaltechAUTHORS:20140218-133808799">"Vectored immunoprophylaxis protects humanized mice from mucosal HIV transmission,"</a> was supported by the UCLA Center for AIDS Research, the National Institutes of Health, and the Caltech-UCLA Joint Center for Translational Medicine. Caltech biology researchers Alejandro B. Balazs, Yong Ouyang, Christin H. Hong, Joyce Chen, and Steven M. Nguyen also contributed to the study, as well as Dinesh S. Rao of the David Geffen School of Medicine at UCLA and Dong Sung An of the UCLA AIDS Institute.</p></div></div></div>Fri, 07 Feb 2014 00:16:30 +0000kfesenma41989 at http://www.caltech.eduA Detailed Look at HIV in Actionhttp://www.caltech.edu/news/detailed-look-hiv-action-41908
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Researchers gain a better understanding of the virus through electron microscopy</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Katie Neith</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/LadinskyHIV_1000.jpg?itok=VwVrZYk9" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">A tomographic reconstruction of the colon shows the location of large pools of HIV-1 virus particles (in blue) located in the spaces between adjacent cells. The purple objects within each sphere represent the conical cores that are one of the structural hallmarks of the HIV virus. <a href="http://www-prod-storage.cloud.caltech.edu.s3.amazonaws.com/LadinskyHIV.jpeg" target="_blank">(View full-size image)</a></div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Mark Ladinsky/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p><span style="line-height: 1.538em;">The human intestinal tract, or gut, is best known for its role in digestion. But this collection of organs also plays a prominent role in the immune system. In fact, it is one of the first parts of the body that is attacked in the early stages of an HIV infection. Knowing how the virus infects cells and accumulates in this area is critical to developing new therapies for the over 33 million people worldwide living with HIV. Researchers at the California Institute of Technology (Caltech) are the first to have utilized high-resolution electron microscopy to look at HIV infection within the actual tissue of an infected organism, providing perhaps the most detailed characterization yet of HIV infection in the gut.</span></p><p>The team's findings are described in the January 30 issue of <em>PLOS Pathogens</em>.</p><p>"Looking at a real infection within real tissue is a big advance," says Mark Ladinsky, an electron microscope scientist at Caltech and lead author of the paper. "With something like HIV, it's usually very difficult and dangerous to do because the virus is an infectious agent. We used an animal model implanted with human tissue so we can study the actual virus under, essentially, its normal circumstances."</p><p>Ladinsky worked with Pamela Bjorkman, Max Delbrück Professor of Biology at Caltech, to take three-dimensional images of normal cells along with HIV-infected tissues from the gut of a mouse model engineered to have a human immune system. The team used a technique called electron tomography, in which a tissue sample is embedded in plastic and placed under a high-powered microscope. Then the sample is tilted incrementally through a course of 120 degrees, and pictures are taken of it at one-degree intervals. All of the images are then very carefully aligned with one another and, through a process called back projection, turned into a 3-D reconstruction that allows different places within the volume to be viewed one pixel at a time.</p><p>"Most prior electron microscopy studies of HIV have focused on the virus itself or on infection of laboratory-grown cell cultures," says Bjorkman, who is also an investigator with the Howard Hughes Medical Institute. "Ours is the first major electron microscopy study to look at HIV interacting with other cells in the actual gut tissue of an infected animal model."</p><p>By procuring such detailed images, Ladinsky and Bjorkman were able to confirm several observations of HIV made in prior, <em>in vitro</em> studies, including the structure and behavior of the virus as it buds off of infected cells and moves into the surrounding tissue and structural details of HIV budding from cells within an infected tissue. The team also described several novel observations, including the existence of "pools" of HIV in between cells, evidence that HIV can infect new cells both by direct contact or by free viruses in the same tissue, and that pools of HIV can be found deep in the gut.</p><p>"The study suggests that an infected cell releases newly formed viruses in a semisynchronous wave pattern," explains Ladinsky. "It doesn't look like one virus buds off and then another in a random way. Rather, it appears that groups of virus bud off from a given cell within a certain time frame and then, a little while later, another group does the same, and then another, and so on."</p><p>The team came to this conclusion by identifying single infected cells using electron microscopy. Then they looked for HIV particles at different distances from the original cell and saw that the groups of particles were more mature as their distance from the infected cell increased.</p><p>"This finding showed that indeed these cells were producing waves of virus rather than individual ones, which was a neat observation," says Ladinsky.</p><p>In addition to producing waves of virus, infected cells are also thought to spread HIV through direct contact with their neighbors. Bjorkman and Ladinsky were able to visualize this phenomenon, known as a virological synapse, using electron microscopy.</p><p>"We were able to see one cell producing a viral bud that is contacting the cell next to it, suggesting that it's about to infect directly," Ladinsky says. "The space between those two cells represents the virological synapse."</p><p>Finally, the team found pools of HIV accumulating between cells where there was no indication of a virological synapse. This suggested that a virological synapse, which may be protected from some of the body's immune defenses, is not the only way in which HIV can infect new cells. The finding of HIV transfer via free pools of free virus offers hope that treatment with protein-based drugs, such as antibodies, could be an effective means of augmenting or replacing current treatment regimens that use small-molecule antiretroviral drugs.</p><p>"We saw these pools of virus in places where we had not initially expected to see them, down deep in the intestine," he explains. "Most of the immune cells in the gut are found higher up, so finding large amounts of the virus in the crypt regions was surprising."</p><p>The team will continue their efforts to look at HIV and related viruses under natural conditions using additional animal models, and potentially people.</p><p>"The end goal is to look at a native infection in human tissue to get a real picture of how it's working inside the body, and hopefully make a positive difference in fighting this epidemic," says Bjorkman.</p><p>Additional authors on the <em>PLOS Pathogens </em>paper, "Electron Tomography of HIV-1 Infection in Gut-Associated Lymphoid Tissue," are Collin Kieffer, a postdoctoral scholar in biology at Caltech; Gregory Olson and Douglas S. Kwon from the Ragon Institute of Massachusetts General Hospital (MGH), MIT, and Harvard; and Maud Deruaz, Vladimir Vrbanac, and Andrew M. Tager from MGH and Harvard Medical School. The work was supported by the Center for the Structural Biology of Cellular Host Elements in Egress, Trafficking and Assembly of HIV (CHEETAH).</p><p> </p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://www.its.caltech.edu/~bjorker/" class="pr-link">Bjorkman Lab Homepage</a></div><div class="field-item odd"><a href="http://www.youtube.com/watch?v=VRwH3rSjNwQ&amp;list=PLB6401753BB13E367" class="pr-link">Pamela Bjorkman at TEDxCaltech (video)</a></div><div class="field-item even"><a href="http://cheetah.biochem.utah.edu/tissue-em-core.html" class="pr-link">Tissue EM Core - CHEETAH</a></div></div></div>Thu, 30 Jan 2014 20:13:49 +0000katien41908 at http://www.caltech.eduSlipChip Counts Molecules with Chemistry and a Cell Phonehttp://www.caltech.edu/news/slipchip-counts-molecules-chemistry-and-cell-phone-41191
<div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/SlipChip.jpg?itok=6DCQJqnY" alt="" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Caltech/Ismagilov Group</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>In developing nations, rural areas, and even one's own home, limited access to expensive equipment and trained medical professionals can impede the diagnosis and treatment of disease. Many qualitative tests that provide a simple "yes" or "no" answer (like an at-home pregnancy test) have been optimized for use in these resource-limited settings. But few quantitative tests—those able to measure the precise concentration of biomolecules, not just their presence or absence—can be done outside of a laboratory or clinical setting. By leveraging their discovery of the robustness of "digital," or single-molecule quantitative assays, researchers at the California Institute of Technology (Caltech) have demonstrated a method for using a lab-on-a-chip device and a cell phone to determine a concentration of molecules, such as HIV RNA molecules, in a sample. This digital approach can consistently provide accurate quantitative information despite changes in timing, temperature, and lighting conditions, a capability not previously possible using traditional measurements.</p><p>In a study published on November 7 in the journal <em>Analytical Chemistry</em>, researchers in the laboratory of <a href="http://ismagilovlab.caltech.edu/rustem_f_ismagilov/">Rustem Ismagilov</a>, Ethel Wilson Bowles and Robert Bowles Professor of Chemistry and Chemical Engineering, used HIV as the context for testing the robustness of digital assays. In order to assess the progression of HIV and recommend appropriate therapies, doctors must know the concentration of HIV RNA viruses in a patient's bloodstream, called a viral load. The problem is that the viral load tests used in the United States, such as those that rely on amplification of RNA via polymerase chain reaction (PCR), require bulky and expensive equipment, trained personnel, and access to infrastructure such as electricity, all of which are often not available in resource-limited settings. Furthermore, because it is difficult to control the environment in these settings, viral load tests must be "robust," or resilient to changes such as temperature and humidity fluctuations.</p><p>Many traditional approaches for measuring viral load involve converting a small quantity of RNA into DNA, which is then multiplied through DNA amplification—allowing researchers to see how much DNA is present in real time after each round of amplification, by monitoring the varying intensity of a fluorescent dye marking the DNA. These experiments—known as "kinetic" assays—result in a readout reflecting changes in intensity over time, called an amplification curve. To find the original concentration of the beginning bulk RNA sample, the amplification curve is then compared with standard curves representing known concentrations of RNA. Since assays, such as those for HIV, require many rounds of DNA amplification to collect a sufficiently bright fluorescent signal, small errors introduced by changes in environmental conditions can compound exponentially—meaning that these kinetic measurements are not robust enough to withstand changing conditions.</p><p>In this new study, the researchers hypothesized that they could use a digital amplification approach to create a robust quantitative technique. In digital amplification, a sample is split into enough small volumes such that each well contains either a single target molecule or no molecule at all. Ismagilov and his colleagues used a microfluidic device they previously invented, called SlipChip, to compartmentalize single molecules from a sample containing HIV RNA. SlipChip is made up of two credit card-sized plates stacked atop one another; the sample is first added to the interconnected channels of the SlipChip, and with a single "slip" of the top chip, the channels turn into individual wells.<br /><br />In lieu of PCR, the researchers used a different amplification chemistry on this chip called digital reverse transcription-loop-mediated amplification (dRT-LAMP), which produces a bright fluorescent signal in the presence of a target molecule during the amplification process. The dRT-LAMP technique eliminates the need for continuous tracking of the intensity of fluorescence; instead, just one end-point readout measurement is used. The resulting patchwork of "positive" or "negative" wells on the device, in combination with statistical analysis, enables single molecules to be counted.</p><p>"In each well, you are performing a qualitative experiment; the result is like a pregnancy test: either yes or no, positive or negative, for the presence of an HIV RNA molecule," says David Selck, a graduate student in Ismagilov's lab and a first author on the study. "But by doing a couple of thousand qualitative experiments, you end up getting a numerical, quantitative result: the concentration of HIV RNA molecules in the sample. By calculating the concentration from the number of wells that contain fluorescence—and therefore HIV—you're leveraging the robustness of many qualitative 'yes or no' experiments to fulfill the need for a quantitative, numerical result," he says.</p><p>When the researchers compared quantification results from dRT-LAMP to those obtained by the real-time, kinetic version of this chemistry, RT-LAMP, they found that the digital format provided accurate results despite changes in temperature and time, while the kinetic format could not. This finding adds to a body of research that the laboratory has been developing on the robustness of converting analog signals (i.e., a readout reflecting a changing concentration over time) into a series of positive or negative digital signals. Another recent paper, published in the <em>Journal of the American Chemical Society,</em> explored a variation on this analog-to-digital conversion.</p><p>Ismagilov's group also tested a way to take an image of the fluorescence pattern in the wells of the SlipChip and, from that image, determine the viral load—without the use of expensive microscopes or trained staff. They turned to a nearly ubiquitous 21<sup>st</sup>-century technology: the smartphone.<br /><br />The researchers placed the SlipChip in a makeshift darkroom (a shoebox with a hole in the top) and then photographed its wells using a smartphone outfitted with a special filter attachment—so that the smartphone flash would be able to "excite" the fluorescent DNA dye, and the smartphone camera could capture an image of the fluorescence. The resulting images were uploaded to Microsoft SkyDrive, a cloud-based server, where custom software—designed by the researchers—determined the viral load concentration and sent the results back in an email. These capabilities allow the digital approach to perform reliably with automated processing, regardless of how poor the imaging conditions may be. As an example of its simplicity, a 5-year-old child was able to use this cell phone imaging method to obtain quantitative results using strands of RNA extracted from a noninfectious virus (a <a href="http://www.youtube.com/watch?v=yzbnP9znFf8">video</a> of this demonstration is available on the Ismagilov lab's YouTube channel).</p><p>"We were surprised that this cell phone method worked, because both cell phone imaging and automated processing are error prone," Ismagilov says. "Because digital assays involve simply distinguishing positives from negatives, we found that even these error-prone approaches can be used to count single molecules reliably."</p><p>The fact that this method is robust not only to changes in time and temperature but also is amenable to cell phone imaging and automated processing makes it a promising technology for limited-resource settings. "We believe that our findings of the robustness of digital amplification could signal a major paradigm shift in how quantitative measurements are obtained at home, in the field, and in developing countries," Ismagilov says.</p><p>The researchers stress that there is still room for improvement, however. "While in this study we were examining robustness and used purified RNA, the next generation of devices will isolate HIV RNA molecules directly from patients' blood," says Bing Sun, a graduate student in Ismagilov's lab and a first author on the study. "We will also adapt the devices for other viruses, such as hepatitis C. By combining these improvements with the cell phone imaging method, we plan to create something that could actually be used in the real world," Sun adds.</p><p>The paper is titled "Increased Robustness of Single-Molecule Counting with Microfluidics, Digital Isothermal Amplification, and a Mobile Phone versus Real-Time Kinetic Measurements." In addition to Selck, Sun, and Ismagilov, the paper is coauthored by Mikhail A. Karymov, an associate scientist at Caltech. The work was funded by the Defense Advanced Research Projects Agency award number HR0011-11-2-0006, and by the National Institutes of Health award numbers R01EB012946 and 5DP1OD003584. Microfluid technologies developed by Ismagilov's group have been licensed to Emerald BioStructures, Randance Technologies, and SlipChip LLC.</p></div></div></div>Fri, 15 Nov 2013 17:25:10 +0000jsconrad41191 at http://www.caltech.eduTraveling with Purposehttp://www.caltech.edu/news/traveling-purpose-36879
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Biologist spends summer vacation volunteering in India</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Katie Neith</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/IMG_2142.jpeg?itok=pzB56hCi" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Children at the Udayan orphanage near Jaipur, India, attend daily meditation sessions that pay homage to all gods.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Pamela Bjorkman</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Pamela Bjorkman has been <span style="line-height: 20.0063037872314px;">studying HIV</span> at Caltech since 2005. In the lab, she has made significant gains in the fight against the virus, developing antibodies that neutralize most strains. But years spent at the bench were beginning to make her feel disconnected from the possible impact of her work. So this summer she visited India, spending time with HIV-positive women and others who are at risk.</p><p>"What I wanted to do was see the real side of HIV, where it affects people," says Bjorkman, the Max Delbrück Professor of Biology and an investigator with the Howard Hughes Medical Institute. "We work in the lab where we have no contact with HIV-infected people—the human impact of the disease is very removed from what we think about in our work."</p><p>This was not her first trip to the nation of over 1.2 billion people, where nearly 30 percent of the population lives in poverty. She first visited in 1985 and returned with her teenage daughter in 2008 to work at an orphanage in the Jaipur area called Udayan. The home for children is part of an umbrella organization called Vatsalya that also runs an HIV-education program for female sex workers, among other projects aimed at empowering women and teaching street children vocational skills.</p><p>"The orphanage is really incredible," says Bjorkman, whose daughter accompanied her on her most recent trip as well. "There are an estimated 18 million children living on the street in India—a lot who are not actually orphans, but on the street anyway. The organization takes in as many children as it can—around 60—and those kids are never adopted. When they come to the orphanage, the group there becomes their family."</p><p>The mission of the organization—founded in 1995 by Jaimala and Hitesh Gupta, both of whom have backgrounds in public health—is to "provide a caring environment where our disadvantaged and vulnerable people can develop their capabilities with dignity." The orphanage is a nearly self-sufficient compound that includes a school, a farm, a garden, and dormitories. They even have a psychologist who visits with the children, many of whom suffered abuse at very young ages.</p><p>"It's really an amazing place," says Bjorkman. "Here these kids are, all living with the most horrible back stories, and they are full of joy and respectful and helpful. It makes you realize how incredibly privileged we are here in Pasadena and that we take a lot for granted."</p><p>Bjorkman and her daughter stayed at Udayan for two weeks each time they visited, helping to teach the children English and math, participating in art and dance projects, and helping with gardening and cooking. This summer, Bjorkman also traveled to Ajmer, where the group's HIV-education program is located. There, she met with women struggling with the stigma of HIV, particularly because they rely on sex work to support their children and send them to private school; public schools in many impoverished areas of India are notoriously bad.</p><p>"The organization identifies women in the community who are sex workers and are interested in learning some other trade, or who need help because of HIV infection," she explains. "The terrible thing is that when they find out they are HIV infected, many of the women start working more because their futures are more uncertain. Plus, they hesitate to take medication because if anyone finds out that they are positive, they will lose customers." </p><p>The organization provides counseling, runs a female condom education program, offers training classes for those wanting to become proficient at another job, and works to get HIV-positive women on antiretroviral medications. While visiting with the women, Bjorkman talked with them about how the virus works and why it's so tough to treat once it's in the body.</p><p>"This is the reason that I'm doing the HIV research," she says. "It's not to get our own papers out first, it's to actually do something that might make a difference. Meeting the women put a lot of the competition and the unpleasantness associated with the rat race of science into perspective."</p><p>Bjorkman plans to return to India, but in the meantime she's doing all she can to raise awareness for Vatsalya and their various projects. Like any nonprofit, the organization could use monetary donations, but she hopes that her story inspires others at Caltech to donate their time. Anyone, she says, can volunteer through Vatsalya and receive room, board, and meals at the orphanage for a nominal daily donation.</p><p>"Caltech undergrad and grad students don't necessarily have that much money, but they may have time and this would be an amazing way to get to know another culture," she says. "These people are really doing a great job—both with the orphanage and with the HIV program that I had direct experience with. Once you see the way it works, it's really inspiring."</p><p>For more information on Vatsalya and the work they do, visit their <a href="http://www.vatsalya.org">website</a>. Or contact <a href="http://www.its.caltech.edu/~bjorker/labdir.html">Pamela Bjorkman</a> to find out how you can become directly involved with this organization. </p></div></div></div>Mon, 08 Oct 2012 21:49:03 +0000katien36879 at http://www.caltech.eduNew Professor Uses Chemistry and Chemical Engineering to Make a Differencehttp://www.caltech.edu/news/new-professor-uses-chemistry-and-chemical-engineering-make-difference-2025
<div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Kimm Fesenmaier</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/SlipChip-for-IsmagilovSPOTLIGHT.jpg?itok=W9mhn1ot" alt="" /><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Caltech/Ismagilov Group</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>Rustem Ismagilov, the new John W. and Herberta M. Miles Professor of Chemistry and Chemical Engineering at Caltech, believes in the ability of science and technology to address significant societal problems—from the spread of HIV and drug resistance to bacterial imbalances in the gut.</p><p>There's always a lot happening in the Ismagilov lab. Some people are working on fundamental science to enable the development of new microfluidic devices—tools that control the flow of very small volumes of fluids through miniscule channels. Meanwhile, others are applying these technologies to answer questions related to the nature of complex biological systems and to address problems such as global-health issues, applications which often demand them to push the frontiers of chemistry and chemical engineering. </p><p>"We love discovering new things on the science side," Ismagilov says, "but we also want to take those new things and do something with them that ultimately makes societal impact."</p><p>One project his lab has been working on is the development of a test to quantitatively diagnose disease almost anywhere—even "on a bicycle in Africa," as Ismagilov likes to say. The World Health Organization is pushing for the development of a viral-load test, which could accurately measure the concentration of viruses, such as HIV or hepatitis C, in the bloodstream, in resource-limited settings. Such an HIV viral-load test is important for monitoring the emergence of drug resistance and to curb its spread among the community. The problem is that the viral-load tests used in the United States require bulky and expensive equipment.</p><p>Ismagilov has come up with an alternative: a microfluidic device that he calls the SlipChip. Essentially, it turns a quantitative measurement, where the desired output is a specific number, into many qualitative, thumbs-up or thumbs-down questions. The basic idea is to split a sample into volumes small enough that each either contains a single viral RNA molecule or it doesn't, and to chemically test each volume for the presence of the virus.</p><p>The SlipChip is made up of two credit card–sized glass or plastic plates stacked atop one another. In the simplest set-up, the bottom plate includes a series of reagent-holding wells. The user injects a sample into a separate path, filling a set of wells and ducts. Then, with just a twist of the top plate, the sample gets separated into discrete volumes and brought into contact with the reagents, where reactions take place if specified concentrations of viral molecules are present. The plates can be made to have wells of different volumes, and the setup can be calibrated to test for different concentrations of viral molecules. </p><p>"It's a really cool way of manipulating lots of small volumes in parallel," Ismagilov says. "What we are really trying to go for is the development of chemistries that will allow us to read things out with a cell phone," Ismagilov says.</p><p>The technique holds promise beyond its potential use in diagnostics in the developing world. "If we can make it robust enough to be used in the real world, I really also think it will revolutionize how we do many experiments in chemistry and biology," Ismagilov says. "Scientists<a name="_GoBack" id="_GoBack"></a> are discovering that the world is complex and heterogeneous—many macromolecules are different, all cells are different. Being able to do these kinds of digital experiments for biology and chemistry would be pretty awesome."</p><p>For example, he says, think about running an experiment in a flask where a million cells are producing a million molecules of antibiotic. It could be that each cell is producing one molecule, or alternately, one cell could be in overdrive, producing a million molecules. "It's pretty hard and tedious right now to get a quantitative handle on things like that," Ismagilov says. "And scientists are discovering that in diagnostics and cancer, there are very critical subpopulations that control outcomes."</p><p>The SlipChip project is just one of several avenues of research currently being pursued in the Ismagilov lab. Another project aims to develop "microbiome-in-a-pill" particles, which could one day deliver spatially structured mixes of needed bacteria in order to prevent or treat conditions associated with microbial imbalance, such as inflammatory bowel disease and colitis. To read more about that new project, click <a href="http://features.caltech.edu/features/271">here</a>.</p><p>Microfluid technologies developed by Ismagilov's group have been licensed to Emerald BioStructures, Randance Technologies, and SlipChip LLC.</p><p>Before coming to Caltech, Ismagilov was a professor of chemistry at the University of Chicago, having worked his way up the ranks after joining the faculty there in 2001. He graduated from Higher Chemical College of the Russian Academy of Sciences in Moscow and earned his PhD in physical organic chemistry at the University of Wisconsin–Madison.</p><p>It might be hard to believe, but there was a time when chemistry was Ismagilov's most troubling subject. Growing up in the former Soviet Union, he was introduced to chemistry at an early age. After receiving failing grades on a couple homework assignments, he went home and read the entire textbook. Then he read the textbook for the next year and the next, eventually reading a college-level chemistry book. Yet he still found himself failing. Finally, perplexed, he went to speak with his teacher and found out that his was a different edition of the book, making his multiple-choice answers incorrect.</p><p>"By that time, I'd gone through the exercise of learning all of this stuff, and chemistry seemed pretty interesting," Ismagilov says. The rest, as they say, is history.</p><p>Click <a href="http://ismagilovlab.caltech.edu/multimedia/slip_chip_movies.shtml">here</a>, to watch animations of some SlipChip setups. </p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://ismagilovlab.caltech.edu/" class="pr-link">Ismagilov Group</a></div></div></div>Thu, 08 Dec 2011 16:00:00 +0000admin2025 at http://www.caltech.eduBiologists Deliver Neutralizing Antibodies that Protect Against HIV Infection in Micehttp://www.caltech.edu/news/biologists-deliver-neutralizing-antibodies-protect-against-hiv-infection-mice-1740
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Process represents novel approach to HIV prevention</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Katie Neith</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/CT_Baltimore_Sphere_SPOTLIGHT.jpg?itok=cQAuKK4Y" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">An illustration shows the crystal structure of the adeno-associated virus used to deliver broadly neutralizing antibodies as Vectored ImmunoProhylaxis against HIV.</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Alejandro Balazs / California Institute of Technology</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.—Over the past year, researchers at the California Institute of Technology (Caltech), and around the world, have been studying a group of potent antibodies that have the ability to neutralize HIV in the lab; their hope is that they may learn how to create a vaccine that makes antibodies with similar properties. Now, biologists at Caltech led by Nobel Laureate David Baltimore, president emeritus and Robert Andrews Millikan Professor of Biology, have taken one step closer to that goal: they have developed a way to deliver these antibodies to mice and, in so doing, have effectively protected them from HIV infection. </p><p>This new approach to HIV prevention—called Vectored ImmunoProphylaxis, or VIP—is outlined in the November 30 advance online publication of the journal <em>Nature</em>.</p><p>Traditional efforts to develop a vaccine against HIV have been centered on designing substances that provoke an effective immune response—either in the form of antibodies to block infection or T cells that attack infected cells. With VIP, protective antibodies are being provided up front.</p><p>"VIP has a similar effect to a vaccine, but without ever calling on the immune system to do any of the work," says Alejandro Balazs, lead author of the study and a postdoctoral scholar in Baltimore's lab. "Normally, you put an antigen or killed bacteria or <em>something</em> into the body, and the immune system figures out how to make an antibody against it. We've taken that whole part out of the equation."</p><p>Because mice are not sensitive to HIV, the researchers used specialized mice carrying human immune cells that are able to grow HIV. They utilized an adeno-associated virus (AAV)—a small, harmless virus that has been useful in gene-therapy trials—as a carrier to deliver genes that are able to specify antibody production. The AAV was injected into the leg muscle of mice, and the muscle cells then put broadly neutralizing antibodies into the animals' circulatory systems. After just a single AAV injection, the mice produced high concentrations of these antibodies for the rest of their lives, as shown by intermittent sampling of their blood. Remarkably, these antibodies protected the mice from infection when the researchers exposed them to HIV intravenously.</p><p>The team points out that the leap from mice to humans is large—the fact that the approach works in mice does not necessarily mean it will be successful in humans. Still, the researchers believe that the large amounts of antibodies that the mice were able to produce—coupled with the finding that a relatively small amount of antibody has proved protective in the mice—may translate into human protection against HIV infection.</p><p>"We're not promising that we've actually solved the human problem," says Baltimore. "But the evidence for prevention in these mice is very clear."</p><p>The paper also notes that in the mouse model, VIP worked even in the face of increased exposure to HIV. To test the efficacy of the antibody, the researchers started with a virus dose of one nanogram, which was enough to infect the majority of the mice who received it. When they saw that the mice given VIP could withstand that dose, they continued to bump it up until they were challenging them with 125 nanograms of virus.</p><p>"We expected that at some dose, the antibodies would fail to protect the mice, but it never did—even when we gave mice 100 times more HIV than would be needed to infect 7 out of 8 mice," says Balazs. "All of the exposures in this work were significantly larger than a human being would be likely to encounter."</p><p>He points out that this outcome likely had more to do with the properties of the antibody that was tested than the method, but adds that VIP is what enabled the large amount of this powerful antibody to circulate through the mice and fight the virus. Furthermore, VIP is a platform technique, meaning that as more potent neutralizing antibodies are isolated or developed for HIV or other infectious organisms, they can also be delivered using this method.</p><p>"If humans are like mice, then we have devised a way to protect against the transmission of HIV from person to person," says Baltimore. "But that is a huge <em>if</em>, and so the next step is to try to find out whether humans behave like mice."</p><p>He says the team is currently in the process of developing a plan to test their method in human clinical trials. The initial tests will ask whether the AAV vector can program the muscle of humans to make levels of antibody that would be expected to be protective against HIV.</p><p>"In typical vaccine studies, those inoculated usually mount an immune response—you just don't know if it's going to work to fight the virus," explains Balazs. "In this case, because we already know that the antibodies work, my opinion is that if we can induce production of sufficient antibody in people, then the odds that VIP will be successful are actually pretty high."</p><p>The study, "Antibody-based Protection Against HIV Infection by Vectored ImmunoProphylaxis," was funded by the Bill and Melinda Gates Foundation, the National Institutes of Health, and the Caltech-UCLA Joint Center for Translational Medicine. Caltech biology researchers Joyce Chen, Christin M. Hong, and Lili Yang also contributed to the paper, as well as Dinesh Rao, a hematologist from the University of California, Los Angeles. </p></div></div></div><div class="field field-name-field-pr-links field-type-link-field field-label-above"><div class="field-label">Related Links:&nbsp;</div><div class="field-items"><div class="field-item even"><a href="http://images.caltech.edu/news_releases/2011_11_30_baltimore/" class="pr-link">Vectored ImmunoProphylaxis: video and additional images</a></div></div></div>Wed, 30 Nov 2011 16:00:00 +0000katien1740 at http://www.caltech.eduBuilding Better HIV Antibodies http://www.caltech.edu/news/building-better-hiv-antibodies-1735
<div class="field field-name-field-subtitle field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">Caltech biologists create neutralizing antibody that shows increased potency</div></div></div><div class="field field-name-news-writer field-type-ds field-label-inline clearfix"><div class="field-label">News Writer:&nbsp;</div><div class="field-items"><div class="field-item even">Katie Neith</div></div></div><div class="field field-name-field-images field-type-file field-label-hidden"><div class="field-items"><div class="field-item even"><div class="ds-1col file file-image file-image-jpeg view-mode-full_grid_9 clearfix ">
<img src="http://s3-us-west-1.amazonaws.com/www-prod-storage.cloud.caltech.edu/styles/article_photo/s3/CT_Bjorkman_SPOTLIGHT.jpg?itok=6vX7J4kv" alt="" /><div class="field field-name-field-caption field-type-text field-label-hidden"><div class="field-items"><div class="field-item even">The increased potency of a new HIV antibody (green and blue), is explained by an insertion (pink) that contacts the inner domain of the HIV gp120 spike protein (yellow). ï¿¼</div></div></div><div class="field field-name-credit-sane-label field-type-ds field-label-hidden"><div class="field-items"><div class="field-item even">Credit: Ron Diskin/Caltech</div></div></div></div></div></div></div><div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p>PASADENA, Calif.—Using highly potent antibodies isolated from HIV-positive people, researchers have recently begun to identify ways to broadly neutralize the many possible subtypes of HIV. Now, a team led by biologists at the California Institute of Technology (Caltech) has built upon one of these naturally occurring antibodies to create a stronger version they believe is a better candidate for clinical applications.</p><p>Current advances in isolating antibodies from HIV-infected individuals have allowed for the discovery of a large number of new, broadly neutralizing anti-HIV antibodies directed against the host receptor (CD4) binding site—a functional site on the surface of the virus that allows for cell entry and infection. Using a technique known as structure-based rational design, the team modified one already-known and particularly potent antibody—NIH45-46—so that it can target the binding site in a different and more powerful way. A study outlining their process was published in the October 27 issue of <em>Science Express</em>.</p><p>"NIH45-46 was already one of the most broad and potent of the known anti-HIV antibodies," says Pamela Bjorkman, Max Delbrück Professor of Biology at Caltech and senior author on the study. "Our new antibody is now arguably the best of the currently available, broadly neutralizing anti-HIV antibodies."</p><p>By conducting structural studies, the researchers were able to identify how NIH45-46 interacted with gp120—a protein on the surface of the virus that's required for the successful entry of HIV into cells—to neutralize the virus. Using this information, they were able to create a new antibody (dubbed NIH45-46<sup>G54W</sup>) that is better able to grab onto and interfere with gp120. This improves the antibody's breadth—or extent to which it effectively targets many subtypes of HIV—and potency by an order of magnitude, according to Ron Diskin, a postdoctoral scholar in Bjorkman's lab at Caltech and the paper's lead author.</p><p>"Not only did we design an improved version of NIH45-46, our structural data are calling into question previous assumptions about how to make a vaccine in order to elicit such antibodies," says Diskin. "We hope that these observations will help to guide and improve future immunogen design."</p><p>By improving the efficacy of antibodies that can neutralize HIV, the researchers point to the possibility of clinical testing for NIH45-46<sup>G54W</sup> and other antibodies as therapeutic agents. It's also plausible that understanding effective neutralization by powerful antibodies may be useful in vaccine development. </p><p>"The results uncover the structural underpinnings of anti-HIV antibody breadth and potency, offer a new view of neutralization by CD4-binding site anti-HIV antibodies, and establish principles that may enable the creation of a new group of HIV therapeutics," says Bjorkman, who is also a Howard Hughes Medical Institute investigator.</p><p>Other Caltech authors on the study, "Increasing the Potency and Breadth of an HIV Antibody by Using Structure-Based Rational Design," include Paola M. Marcovecchio, Anthony P. West, Jr., Han Gao, and Priyanthi N.P. Gnanapragasm. Johannes Scheid, Florian Klein, Alexander Abadir, and Michel Nussenweig from Rockefeller University, and Michael Seaman from Beth Israel Deaconess Medical Center in Boston also contributed to the paper. The research was funded by the Bill &amp; Melinda Gates Foundation, the National Institutes of Health, the Gordon and Betty Moore Foundation, and the German Research Foundation.</p></div></div></div>Fri, 28 Oct 2011 01:00:00 +0000katien1735 at http://www.caltech.edu